isXander
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Splitscreen Mod Alpha 2
🕑 Added 2025-06-03 21:04:11 +0000 UTCThis time we get server authentication, fullscreen, and basic audio handling!
This will likely be the last build that targets 1.21.5 as 1.21.6 is imminent!
How to use
If this is your first time with Splitscreen Mod, you're in luck! It just got a lot easier. Alpha 2 introduced support for the Modrinth App, and as such, this version is distributed as a .mrpack (the modrinth modpack format). It contains all mods you need, you just open it in the Modrinth App and have fun!
Multiplayer features
Splitscreen Mod can now be added as a server-side mod, permitting players that use the splitscreen mod.
Only the host player needs to own a Minecraft account, the server will securely authenticate the rest of the players using the host player.
Servers are strict in requirements;
they can limit the amount of "sub-players" that can join in this way;
they also enforce the username format to be <HostPlayer>.<index>, they must be sequential. For example, if isXander is the host, sub-players can be named isXander.1, isXander.2, etc.
whilst this is limited to Fabric for now, a limited implementation may be possible for PaperMC/Spigot later down the line if requested
You still cannot currently join servers which do not have the Splitscreen Mod installed.
Supporting servers also now bundle sound event packets together and send them only to the host/controller client, where the controller can decide how to handle the audio. Previously, sounds would duplicate for each player. This functionality has not been fully implemented, as so, only sound events audible from the controller player will be played, and only from their perspective.
Music has also been temporarily disabled as each client played their own music. Some foundations have been set in place in this build for the controller to decide which music track to player based on order of importance, e.g., boss fight music from player 2 over the ambient biome music from player 1.
Fullscreen support
Splitscreen Mod now features fullscreen support! I have utilised Borderless Fullscreen as it is currently the only method of fullscreen that will work with the current splitscreen technique.
Due to the abnormal window properties of the splitscreen window, there may be some bugs. For example, in this version turning off fullscreen makes the window slightly smaller than it was previously, potentially bumping down to the next GUI scale.
Other Changes
There's also a config screen now in the Options menu. You can adjust the splitscreen setting to go into a vertical orientation instead of horizontal, if that's what you prefer. (The other settings in that menu don't work)
Just after releasing Alpha 1, I got started on reworking the code behind the scenes to set Splitscreen Mod up for the future; the whole technique of splitscreen has been abstracted so other methods can be developed that can work on operating systems other than Windows in the future.
If one of the players disconnects for whatever reason, the mod will attempt to detect this and kick all players and show a single unified disconnected error screen.
What's next?
In the short term, I want to work on getting multiplayer working on servers without the Splitscreen Mod. This will be done by requiring each player sign in with their own Minecraft account from in-game. I'd also like to get sound and music handling in a better state.
Comments
isXander
i’d hope that three-player works, but as I only own two controllers, it’s been impossible for me to test this
isXander
at least during this beta period, splitscreen will only be available for the latest version of minecraft available at the time of release, this is to allow more rapid development as i’m not spending my time maintaining multiple targets
Joel Spiers
Great mod this is definitely a step in the right direction! Is three players functional or in the making. I’ve tested it and it seems to position the screens correctly but will get an unplayable window for the third player. Appreciate all of the work you put into this so far keep up the good work!
s1xxu
is this possible to get a 1.21.1 version?
isXander
The whole process of splitscreen launching a new client is very brittle and launchers can break it. I had to get Prism Launcher to implement a patch to allow it to work, I have tested Modrinth App. ATLauncher may very well work, I suggest you try it and see, I’m just not familiar with it and haven’t tested it
